NMR studies of nucleotide conformation and nucleotide interactions were partly directed toward the elucidation of the molecular structures of the self-associated form of guanosine-5'-phosphate at neutral pH. By direct measurement of one of the equilibria by proton NMR we found that the association leads to an octamer, the detailed structure of which has been deduced from molecular models and other NMR measurements. Another major area of interest was the study of polynucleotides in nucleosome core particles. In poly(dAdT).poly(dAdT) of 145 base pairs 31P NMR studies showed that the phosphate backbone probably has an alternating conformation. Strategies for measuring NMR spin-lattice relaxation times have been explored from the standpoint of minimizing random errors and thus decreasing the instrumental time required to make such measurements. Modified methods have been proposed to alleviate certain systematic errors found in conventional procedures.